docs(platform): accept protected mainline recovery

[zhouning]

Summary

• accept ADR-035 with the verified mainline recovery record and final SHAs
• make staging candidate publication manual-only from refs/heads/main
• restrict the protected provenance verifier to successful workflow_dispatch publishers
• update workflow contract tests and ADR-033 for the explicit publication boundary

Verification

• 24 staging candidate, registry, provenance, and release tests passed
• platform truth validation passed
• workflow YAML parsing passed
• Ruff and git diff checks passed
• post-switch main CI run 30199837779 passed frontend, platform, and full agent evaluation

Boundary

This PR does not publish a candidate and does not deploy staging or production.